Cosmic Queries: Space Probes with Dr. Amy Mainzer

JPL astrophysicist Dr. Amy Mainzer is back as guest host for this week’s podcast, and together with comic co-host Chuck Nice she answers your questions about space probes.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:21Speaker 01

  Hi everybody and welcome to StarTalk Radio. My name is Amy Mainzer and I'm an astronomer at the Jet Propulsion Laboratory in Pasadena, California and I'm here guest hosting. I'm here with my wonderful co-host Chuck Nice.

• 0:35Chuck Nice?

  Hey Amy, how are you?

• 0:36Speaker 01

  I'm doing great.

• 0:37Chuck Nice?

  Yeah, yeah, good to see you, good to be here with you.

• 0:40Speaker 01

  Yeah, and today we are going to talk about spacecraft.

• 0:43Chuck Nice?

  Yes, that's right, space probes. And something you would know about, because as we have talked off the air, I found out that you were an engineer for quite some time with Lockheed Martin and building spacecraft.

• 0:58Speaker 01

  Yes, that was my other life, my alter ego.

• 1:00Chuck Nice?

  You know, and it's so weird because when I think about Lockheed Martin, what comes to mind, I envision like the underground layer of a Bond villain. You know, like there's no walls, there's just rock and titanium everywhere and guys walking around in white jumpsuits with clipboards and hard hats. That's, you know, what's it like, do you have a security clearance, number one?

• 1:23Speaker 01

  No security clearance, but I would say there were a lot more guys wearing socks with sandals. Lots of socks with sandals. There was one really cool tunnel that went a long ways and the walls were made out of rock.

• 1:38Chuck Nice?

  Yeah?

• 1:39Speaker 01

  Oh, yeah, actually they were.

• 1:40Chuck Nice?

  Okay, I'll take that.

• 1:41Speaker 01

  That was kind of cool.

• 1:42Chuck Nice?

  I'll take that.

• 1:43Speaker 01

  But socks with sandals.

• 1:44Chuck Nice?

  All right, well, listen, you know, we have Cosmic Queries, what we do is we take questions from all over the internet and all of the outlets where we are found and people just write in things they want to know about and this is right up your alley, so you will answer them. So you ready to get into it?

• 2:00Speaker 01

  Sure, let's go.

• 2:01Chuck Nice?

  All right, here we go. Let's start off with David Spitzer, who has a two-part question. Where would you most be interested in sending a probe?

• 2:10Chuck Nice?

  And of the upcoming missions, which interests or excites you most? A little personal there from David.

• 2:16Speaker 01

  Sure. Well, there are so many great places to explore in our solar system and beyond it. And the robots that we send out are basically our eyes and our ears. They can go places and see things that our fragile human bodies pretty much just can't do. So they can go places like, for example, into the surface of Europa. Or maybe even into the ice of Europa. I personally think that would be a pretty cool place to go.

• 2:41Chuck Nice?

  Right.

• 2:41Speaker 01

  Because Europa is a moon of Jupiter and they think that it has a liquid water ocean underneath a very icy surface. So who knows? Maybe there's space squids under there.

• 2:50Chuck Nice?

  Right.

• 2:50Speaker 01

  That would be fun.

• 2:51Chuck Nice?

  Nice. So there you have it. Probes to Europa. That floats your boat personally is what you're saying.

• 2:57Speaker 01

  So to speak, yes.

• 2:58Chuck Nice?

  Right, because on Europa, it would, it'd be more like that skis your ice. I don't know.

• 3:04Speaker 01

  Yeah, something like that.

• 3:05Chuck Nice?

  Something like that. Who knows? Okay. All right. So now, you know, when we're talking about probes, uh, you know, these are spaceships, basically.

• 3:13Speaker 01

  Right.

• 3:13Chuck Nice?

  That, that we're sending out to look for things. And, uh, here is something that Logan keeps tweets at Tweets by L K. Now, are asteroid fields, and she says, think Star Wars, really dangerous? Or is there enough room between the rocks to navigate? So that makes sense. If we're going past our solar system, how do you get past the asteroid belt?

• 3:39Speaker 01

  You know, when astronomers first thought about sending spacecraft out into the outer reaches of the solar system, like the pioneers and the Voyager missions, at first they were very worried about this exact thing. The asteroid belt is full of asteroids between Mars and Jupiter, and we know that at least 600,000 of these asteroids there today. The thing is, is, is it like the Empire Strikes Back? You know, that scene where Han Solo is trying to give Darth Vader the slip, right?

• 4:02Chuck Nice?

  Absolutely.

• 4:03Speaker 01

  Got to dodge among all the space rocks. Well, eh, no.

• 4:06Chuck Nice?

  No.

• 4:07Speaker 01

  No, it's one of the great disappointments of an asteroid scientist. When you're, when you're first starting out in the field, you realize that actually the asteroids are big, but space is bigger.

• 4:16Chuck Nice?

  Right.

• 4:17Speaker 01

  And there's a tremendous amount of room between all of these space rocks.

• 4:21Chuck Nice?

  So it's a very comfortable commute.

• 4:23Speaker 01

  Yes, it's not so bad.

• 4:27Chuck Nice?

  So it really isn't, you don't need the Millennium Falcon to get through an asteroid.

• 4:31Speaker 01

  Unfortunately not. I wish I had a Millennium Falcon, though.

• 4:34Chuck Nice?

  Don't we all?

• 4:35Speaker 01

  Yes, everyone need one.

• 4:36Chuck Nice?

  Yeah, I take it to work every day. You kidding me? That'd be awesome. So, and, and speaking of that scene, okay. Completely, right? Completely unfathomable that a giant space lizard could live on an asteroid, right?

• 4:48Speaker 01

  Yeah, unfortunately, unfortunately. I mean, I, you know, space lizards are cool, but we don't know of any actually in real life. It's probably a good thing.

• 4:56Chuck Nice?

  All right, let's move on from Facebook. This is, uh, Carrie Carell, who says, what is the single most important thing we've learned through data sent by a space probe? Have we learned anything that prior to launching probes, we had never even contemplated previously?

• 5:13Speaker 01

  Oh, wow. Okay. So one of the, there have been so many discoveries that have just really changed our understanding of astronomy that have come from space missions. For example, uh, the cosmic background. And then this is something that, uh, was, was first discovered on the ground by radio astronomers. This is an echo left over from the Big Bang itself.

• 5:32Chuck Nice?

  Right.

• 5:33Speaker 01

  Way back in time, thirteen point seven, well, here we go.

• 5:37Chuck Nice?

  Billion years ago.

• 5:39Speaker 01

  Yes, exactly. This is a long time ago, but this radiation is still around and astronomers had found evidence of it on the ground. But when they launched the Cosmic Background Explorer mission, uh, back in the eighties, they were actually able to really precisely tell exactly how old those echoes of light were, and from that tell the age of the universe itself.

• 6:01Chuck Nice?

  Wow. So would you say that's the most important discovery that we have made, uh, once by launching a probe?

• 6:06Speaker 01

  I would say that's one of the big ones. That's a pretty important discovery, the age of the universe. And of course, the Hubble Space Telescope was instrumental in finding other ways to help pin down that number.

• 6:16Chuck Nice?

  Right.

• 6:17Speaker 01

  By measuring the distances of exploding stars called supernovae. So that's another one. I mean, there are just so many examples of where these robots have helped us out.

• 6:25Chuck Nice?

  I just learned that there is a plural for supernova, which is supernovae.

• 6:31Speaker 01

  Yes.

• 6:31Chuck Nice?

  All right.

• 6:32Speaker 01

  We have a special, in fact, the nail polish I am wearing right now is actually called supernova.

• 6:37Chuck Nice?

  And what color is your nail polish? Let me see there. Silver. And, and quite fetching, I must say.

• 6:43Speaker 01

  Thank you. Very sparkly.

• 6:44Chuck Nice?

  Very sparkly.

• 6:45Speaker 01

  For a supernova, that's what you want.

• 6:50Chuck Nice?

  Supernova.

• 6:51Speaker 01

  Yeah.

• 6:51Chuck Nice?

  Cool. The only supernova ever in my life was a Chevy and it wasn't so super.

• 6:57Speaker 01

  It wasn't so super.

• 6:59Chuck Nice?

  All right, let's move on. Scott McGregor wants to know this. What's the most important probe in use today? The rock star of probes, the one to watch. Also, can we look forward to it in terms of new probe technologies?

• 7:15Speaker 01

  Right. Okay, so I have a personal couple of favorites. Everybody knows and loves the Hubble Space Telescope. That's one of our biggest workhorse telescopes that we use as astronomers to look at everything from the distant universe to very nearby things. I also have a fan, I'm a big fan of smaller things like the Wide Field Infrared Survey Explorer, a little infrared telescope. It's a heat seeking telescope and it's seen an awful lot of asteroids.

• 7:40Chuck Nice?

  Nice.

• 7:40Speaker 01

  Yeah, so we've got, hopefully, we've got a few new things coming up on the horizon that'll really expand our knowledge of the universe.

• 7:47Chuck Nice?

  But that's classified, buddy.

• 7:50Speaker 01

  Okay, well, we're gonna take a short break here, so more when we come back to StarTalk Radio.

• 8:13Speaker 01

  And we're back to StarTalk Radio. I'm your guest host, Amy Mainzer, from the Jet Propulsion Lab, and I'm here with my co-host, Chuck Nice.

• 8:20Chuck Nice?

  Hey, Amy.

• 8:21Speaker 01

  Hi.

• 8:22Chuck Nice?

  How are you? Of course, we're doing Cosmic Queries: Space Probes, and let's jump right back into the questions. This one from Google Plus, and Stephen Woolery would like to know this. Do you think it's worth spending limited science budgets on smaller, purpose-built missions like WISE, which you mentioned already today, or is it better to invest in larger, more diverse missions like Webb?

• 8:50Speaker 01

  This is a very, very important point and question here for NASA and how we decide our priorities. I'm a big fan of having a mix of missions. I like not putting all of my eggs in one basket. So I like to be able to have, I'd like to see us be able to do a mix of small missions, some medium missions, and one or two really big ones. But, you know, if you have only one thing, then you kind of can't do certain classes of science.

• 9:13Chuck Nice?

  Right.

• 9:14Speaker 01

  Some missions don't need a big giant Battlestar Galactica. And other questions you can only answer with some fairly big stuff. So I think having a mix is a really good idea.

• 9:23Chuck Nice?

  Cool, cool. So there you have it. Got to mix it up.

• 9:27Speaker 01

  Yeah.

• 9:28Chuck Nice?

  So do we think that we'll ever see a refunding of NASA? Or is it going to continue to be a constant stripping away of funds? Because the dummies in Congress don't see the value in what we do when we glean things from, knowledge from space.

• 9:47Speaker 01

  Well, one thing that gives me hope is all the people who are listening to StarTalk Radio right now. I mean, there are people who love space.

• 9:53Chuck Nice?

  Yes.

• 9:54Speaker 01

  And if you love space, say so. Tell your neighbors, tell your friends, tell your kids. Because that's how we get to do all of this stuff. When people demand that we explore our universe, that we learn more about it, then we get to do that. Because our Congress and our Senate, they hear us when we talk to them, so.

• 10:11Chuck Nice?

  The squeaky hinge gets the oil.

• 10:13Speaker 01

  Absolutely, absolutely.

• 10:15Chuck Nice?

  Even though there's no noise in space.

• 10:20Chuck Nice?

  All right, very cool. All right, this one from Google Plus. John Mink wants to know this. What tends to be the limitations you run into with probes? Is it size, available power, cost redundancy?

• 10:36Speaker 01

  Mm-hmm.

• 10:37Chuck Nice?

  Is it a combination of things? Or is there always one or two? And how much do these limitations change on different missions?

• 10:43Speaker 01

  Oh, yes. So there are a lot of things that are difficult about launching stuff into space.

• 10:47Chuck Nice?

  Okay.

• 10:47Speaker 01

  Main thing is, it is $10,000 a pound. It is crazy expensive to put something in space.

• 10:54Chuck Nice?

  Ten thousand dollars a pound.

• 10:56Speaker 01

  Yes.

• 10:56Chuck Nice?

  So I would assume lighter materials are priority number one.

• 11:01Speaker 01

  Yes, absolutely. In fact, one time I was thinking about it, what if we wanted to launch what I would call Brick Cam, which is basically to launch a brick into space. It would be very expensive, just to even launch a brick.

• 11:11Chuck Nice?

  Just to launch a brick.

• 11:12Speaker 01

  Yeah, if you really wanted to put it on spacecraft. So yes, mass is key. You've got to get the thing as lightweight and as small as you possibly can. That's the challenge.

• 11:22Chuck Nice?

  So those are the cha- now, and I guess because you build this stuff, or you did at one point in your life, uh, where are we headed? I mean, how close are we to getting something very small, very light, and still very effective?

• 11:37Speaker 01

  Well, I am waiting for someone to invent something that I call unobtanium. This is a material that has zero mass, consumes zero power. I think we could do this, right?

• 11:49Chuck Nice?

  That's awesome.

• 11:50Speaker 01

  I mean.

• 11:50Chuck Nice?

  Unobtanium.

• 11:51Speaker 01

  Unobtanium.

• 11:52Chuck Nice?

  That's good. You and James Cameron.

• 11:54Speaker 01

  There we go. We're working on it.

• 11:55Chuck Nice?

  Working on the same thing.

• 11:59Chuck Nice?

  Awesome. All right. This is from Patrick Dennett from Facebook. Is the reason we haven't sent a rover to Venus that the temperature would be problematic? Or is there some other reason, technical or budgetary, that's stopping this from happening?

• 12:16Speaker 01

  Oh, yes. So Venus is one of these places that is just really tough to explore. It's kind of Earth's evil twin, if you will.

• 12:23Chuck Nice?

  Okay.

• 12:23Speaker 01

  Because even though it's sort of the same size as the Earth, it's about 900 degrees on the surface. It's hot enough to melt lead.

• 12:32Chuck Nice?

  Wow.

• 12:33Speaker 01

  And the atmospheric pressure is about 90 times our surface pressure here on Earth. And then to top it all off, a lot of the atmosphere is sulfuric acid. So take your pick.

• 12:44Chuck Nice?

  Yeah.

• 12:45Speaker 01

  It's not a nice place.

• 12:46Chuck Nice?

  Not a nice place.

• 12:47Speaker 01

  No, and so the question I've always had is, okay, well, what is it that gets your spacecraft first? Is it getting crushed to death? Is it getting cooked or burned by acid?

• 12:56Chuck Nice?

  Right, right, or dissolved by acid.

• 12:58Speaker 01

  Yeah.

• 12:59Chuck Nice?

  So basically, not a very friendly place to go.

• 13:01Speaker 01

  And it turns out, weirdly enough, we think that what really gets these things is actually temperature.

• 13:05Chuck Nice?

  Really?

• 13:06Speaker 01

  Because the Russians did, in fact, land a couple of space probes onto the surface of Venus, and they lasted 45 minutes.

• 13:13Chuck Nice?

  Wow.

• 13:13Speaker 01

  And that was it.

• 13:14Chuck Nice?

  And that was the end of it.

• 13:15Speaker 01

  That was the end.

• 13:16Chuck Nice?

  Look at that. And isn't it funny that Venus is the god of love?

• 13:19Speaker 01

  Yeah.

• 13:20Chuck Nice?

  After all that nastiness you just put out there, that makes no sense to me whatsoever.

• 13:25Speaker 01

  Very true, very true. I would rename it.

• 13:29Chuck Nice?

  All right, here we go. This is, um, Brett A. Verbic wants to know this. The president announced funding for a landing on unmanned craft on an asteroid to lasso it to the moon. Are probes going to be sent to prospect a candidate asteroid? Any news to share about this mission? Now, if I'm not mistaken, I believe the president said 2025 or 2030, something like that?

• 14:01Speaker 01

  Yeah, so our president set out an ambitious goal to go to an asteroid by 2025, I think. And so one of the concepts that's come up is, well, what if we were to bring the asteroid back? And it's a possibility. The thing is, is you have to find exactly the right asteroid. Not, not all asteroids are alike. Some of them are much harder to get to than even getting to Mars. So you'd have to find an asteroid that's in exactly the right orbit that wouldn't cost an enormous amount of fuel to get to and then get back. So that's a toughie. We're, I don't work on this project, but I know other people who do.

• 14:35Chuck Nice?

  Oh, okay, really?

• 14:36Speaker 01

  Oh, yeah, there's a lot of work if they're going to really make that a reality. So we'll see what happens.

• 14:40Chuck Nice?

  Mm-hmm. So now, here's the thing that really disturbs me just a little bit.

• 14:44Speaker 01

  Mm-hmm.

• 14:45Chuck Nice?

  You talk about bringing it back. You know, I kind of get the, the, the feeling like people who go to Florida and bring back a little alligator.

• 14:53Speaker 01

  Yes.

• 14:54Chuck Nice?

  And then it becomes more of a problem than they thought and then they flush it and now I got a big albino monster alligator living in my, in my sewer system. So where exactly are we bringing this asteroid back to?

• 15:07Speaker 01

  There's an alternate concept that isn't so much about bringing back a whole asteroid as just bringing back a small boulder off of one.

• 15:13Chuck Nice?

  Oh, okay.

• 15:14Speaker 01

  Maybe that's a little better.

• 15:15Chuck Nice?

  All right. I'm comfortable with that.

• 15:19Speaker 01

  No alligators.

• 15:22Chuck Nice?

  All right, Rufus from Facebook wants to know this. Would it be possible to send a probe out into space, land on an asteroid, hitch a ride somewhere and then lift off of it again and continue? Kind of like a space bust. If so, could we get farther into space than we would normally be able to?

• 15:43Speaker 01

  Oh, that is, okay, so really cool thing about this, someone's already done it.

• 15:48Chuck Nice?

  What?

• 15:48Speaker 01

  Yeah, the Japanese sent a mission called Hayabusa and it actually went to an asteroid and it landed on it. Even collected a few tiny, tiny little grains off of it.

• 15:58Chuck Nice?

  Right.

• 15:59Speaker 01

  And then it came back.

• 16:00Chuck Nice?

  Sweet.

• 16:01Speaker 01

  And it actually came back and it re-entered the earth's atmosphere, bringing back its very precious sample cargo.

• 16:07Chuck Nice?

  You know, I saw that and what's funny is what came back was this tiny little disc. And that's all it was, was this tiny little like plate, it was like a saucer.

• 16:19Speaker 01

  Yeah, tiny little bits and pieces that came back and so they're sending a second one, it's called Hayabusa 2.

• 16:26Chuck Nice?

  How creative.

• 16:29Speaker 01

  The revenge of Hayabusa, I guess. So they're gonna do it again and they're gonna go to a different asteroid and they're gonna try to bring back more. And we also have another mission that's coming up called Osiris Rex.

• 16:39Chuck Nice?

  Osiris Rex.

• 16:40Speaker 01

  We love our acronyms at NASA. Don't ask me what it stands for. I can't remember. But it's gonna go to an asteroid and collect a sample that with a sampling technique that looks kinda like an air filter on your car. And the idea is it's gonna touch down on the asteroid's surface and fire some gas into it and that's gonna push a bunch of dust and pebbles into this thing that looks like an air filter.

• 17:01Chuck Nice?

  Okay, and that captures it?

• 17:02Speaker 01

  That captures it.

• 17:03Chuck Nice?

  So that will capture all the dust and everything from this little

• 17:06Speaker 01

  Yeah.

• 17:07Chuck Nice?

  And, and then that will come back, I suppose.

• 17:10Speaker 01

  Exactly. And then it returns to Earth and then they're gonna pick it up somewhere. Presumably it's gonna land in some nice backyard or something. I don't know.

• 17:17Chuck Nice?

  Let me ask you this, because I'm fascinated now. You got my curiosity. Do we have international cooperation? Because you can't tell where this thing is gonna land. If you send something out there, it lands on an asteroid and it comes back. You can't say, well, now it's gonna land here, right?

• 17:35Speaker 01

  You know, the crazy thing is they can.

• 17:37Chuck Nice?

  Oh.

• 17:38Speaker 01

  They can do this and they are going to, but they do have to land.

• 17:41Chuck Nice?

  No, when I say, you can't tell. I'm saying, you can't say like, okay, we're gonna make it land here in New York City.

• 17:51Speaker 01

  Right.

• 17:52Chuck Nice?

  That's what I meant to say. Of course, you could tell where it's gonna land.

• 17:55Speaker 01

  Yeah.

• 17:55Chuck Nice?

  But do we have international cooperation so that when it lands in another country, they don't say, what you talking about?

• 18:01Speaker 01

  Yeah, what is this?

• 18:02Chuck Nice?

  This is mine.

• 18:03Speaker 01

  Yeah, well, like Hayabusa landed, I think in Australia, if I remember right. And boy, did they have cool space uniforms for picking up the capsule. So I hope they have cool space uniforms wherever it lands.

• 18:12Chuck Nice?

  Nice, nice.

• 18:14Speaker 01

  All right. Well, it's time for us to take a very short break and then we'll be right back with more cosmic queries on StarTalk Radio. And be sure to check us out on StarTalkRadio.net.

• 18:41Speaker 01

  And we're back with StarTalk Radio. I'm Amy Mainzer, your guest host, and I'm here with my co-host Chuck Nice.

• 18:47Chuck Nice?

  Hey, Amy.

• 18:48Speaker 01

  Shall we talk about some space probes?

• 18:50Chuck Nice?

  Yes, we shall. Every time you say "space probes," I feel so immature. I'm sorry, but I do. I can't help myself. It's just like, "space probe," I'm like, "pretty space probe!" Okay.

• 19:01Speaker 01

  It sounds like aliens.

• 19:02Chuck Nice?

  It really does. But space probe is different from alien probe, so...

• 19:08Chuck Nice?

  Let's not confuse the two. All right, let's move on with our questioning from our audience, and this is Brenton Fetteroff, who wants to know, "Why haven't we sent a probe that can take a core sample of the Martian lunar surface?" Now, my... Here's what I want to know. We do have a rover there, right?

• 19:29Speaker 01

  Oh, yeah. There's a couple rovers.

• 19:30Chuck Nice?

  There's a couple rovers on Mars. It was a big deal.

• 19:33Speaker 01

  Yeah.

• 19:34Chuck Nice?

  So, are we not getting anything back from there?

• 19:37Speaker 01

  We are not, at present, returning samples from Mars. What we're getting back are a lot of pictures. We're getting an incredible amount of photos and data.

• 19:45Chuck Nice?

  Right.

• 19:46Speaker 01

  But it's really hard to get something off the surface of Mars. And that is because Mars has a lot of gravity.

• 19:53Chuck Nice?

  Of course, yeah.

• 19:53Speaker 01

  A lot of gravity.

• 19:54Chuck Nice?

  You have to launch it the same way you launch from Earth.

• 19:57Speaker 01

  Exactly.

• 19:58Chuck Nice?

  So, you would need some type of propulsion system that would be able to clear the gravitational pull of the planet.

• 20:04Speaker 01

  Yep.

• 20:05Chuck Nice?

  And then get back to Earth.

• 20:06Speaker 01

  That's exactly the problem. And so, the thing is, that is really difficult to do, because propulsion means you need fuel, and fuel means it takes mass. You've got to have something to burn to get off the planet. And up until now, that's proven very, very difficult. So, people have plans for what's called a Mars sample return mission.

• 20:24Chuck Nice?

  Mm-hmm.

• 20:25Speaker 01

  But it's not easy, and it's going to take a lot of talent to do that.

• 20:28Chuck Nice?

  So, now, I may be silly, but could we not attach a very long string

• 20:38Chuck Nice?

  to some type of canister and just give it a hell of a yank?

• 20:41Speaker 01

  Yeah. I was thinking catapults, myself. What do you think? Like a trebuchet, you know, like a medieval, you know, sample flinger, right?

• 20:53Speaker 01

  I think we could do this.

• 20:54Chuck Nice?

  So, so just as, just as a quickie though, wouldn't that be feasible to think of instead of a propulsion system, perhaps a, um.

• 21:04Speaker 01

  Like a tether.

• 21:04Chuck Nice?

  Like, not even a tether, but something that would shoot it off the planet.

• 21:08Speaker 01

  Oh, yeah, yeah. So people have talked about these things like railguns.

• 21:12Chuck Nice?

  Like a railgun, right.

• 21:13Speaker 01

  Like that ride, Superman ride at Magic Mountain. Have you been on that one?

• 21:16Chuck Nice?

  Yeah.

• 21:17Speaker 01

  Yeah, it's like.

• 21:18Chuck Nice?

  Like straight off.

• 21:19Speaker 01

  Yeah, people have talked about that and it's, it's just, up until now, it's proven pretty difficult to get something like that to work in practice. Mostly what we rely on is chemical propulsion. That's what most of our rockets use.

• 21:30Chuck Nice?

  So basically that would have to be, uh, if you're gonna do that, you might as well have a manned mission to Mars.

• 21:35Speaker 01

  Yeah, it's pretty tough. I mean, the Mars sample return with robots is probably a lot easier than sending people because people have this annoying habit of wanting air and food and.

• 21:47Chuck Nice?

  Babies.

• 21:48Speaker 01

  Oh, yeah, and you know.

• 21:49Chuck Nice?

  Babies, that's what your problem is.

• 21:51Speaker 01

  It's like, uh, it's kinda hard. We call it the, you know, canned meat flinging, right? I mean, it's, it's just harder than robots in some ways. Robots, they're much tougher.

• 21:59Chuck Nice?

  Right.

• 21:59Speaker 01

  And so they can tolerate things that the human body can't.

• 22:02Chuck Nice?

  Right. Well, one day they'll all be our overlords, so.

• 22:05Speaker 01

  I for one welcome our robot overlords, I think.

• 22:10Chuck Nice?

  All right, here we go. Let's move on to, uh, Fernando Morales Francini, who wants to know, are there any defined candidates for New Horizons to explore after Pluto? So now we've been to Pluto, what's, what's next?

• 22:26Speaker 01

  Right. Well, New Horizons is gonna really whip by Pluto super fast because in order to get to Pluto in any kind of reasonable amount of time, they had to basically do a bunch of slingshot maneuvers to pick up the speed. And so the thing is, they're gonna blast by Pluto and collect a lot of great data. But the question is, could they go somewhere else? And so astronomers have been looking very hard to see if there are any other Kuiper belt objects. These are very icy bodies, far away from our sun, to see if they could find any. And as far as I know, there are no viable candidates at present. That doesn't mean there aren't any. It just means we've got to work harder.

• 23:03Chuck Nice?

  You haven't identified them.

• 23:04Speaker 01

  Yeah, that's right. And part of the problem is Pluto, right now, is in the plane of our galaxy. That's just where it happens to be in its orbit.

• 23:10Chuck Nice?

  Right.

• 23:11Speaker 01

  We're seeing the Milky Way behind it, and that is, there's a lot of stars in there.

• 23:14Chuck Nice?

  Right.

• 23:15Speaker 01

  So picking out a distant faint-moving object is challenging.

• 23:18Chuck Nice?

  Right.

• 23:19Speaker 01

  And they're working on it.

• 23:20Chuck Nice?

  Now, you mentioned slingshotting. Is that a means of propulsion that is common when you're talking about sending something somewhere?

• 23:29Speaker 01

  Yeah. It turns out, this has been one of the key techniques for getting around the solar system. It's funny, you would have never thought this, you know, 50 years ago, that this was possible, but it turns out, to get to some of the most distant parts of the solar system, you've actually got to steal a little bit of energy, of orbital energy, from planets like Jupiter, and even from the Earth itself.

• 23:49Chuck Nice?

  Right. So cool.

• 23:51Speaker 01

  So, yeah.

• 23:52Chuck Nice?

  So, basically, it's like playing pinball.

• 23:53Speaker 01

  Yeah, exactly.

• 23:54Chuck Nice?

  It's like playing pinball.

• 23:55Speaker 01

  It's just like playing pinball. You've got to pick up a little speed by hitting a resonance.

• 23:58Chuck Nice?

  Nice! All right. Let's go to Andrew McBandrews. I wonder if that's a real name. Hello, I'm Andrew McBandrew. Higher priority target with limited NASA funds, Europa or Titan?

• 24:16Speaker 01

  Oh, boy, oh, boy.

• 24:18Chuck Nice?

  He's talking to you personally now. He wants to know, which one do you think is more important?

• 24:22Speaker 01

  Well, I have to say, I really loved getting those images from the Huygens probe as it made its way through Titan's atmosphere. But, you know, Europa looks like an interesting place, too, and we know less about it. So, I think that might be an interesting place to go. In other words, we haven't really been there

• 24:37Chuck Nice?

  Right.

• 24:38Speaker 01

  in person, with a probe going directly there. So, I'd probably vote for Europa at this point.

• 24:42Chuck Nice?

  Yeah, so you've got to go to the place that's, the road less traveled.

• 24:45Speaker 01

  Try something new.

• 24:46Chuck Nice?

  Try something new.

• 24:47Speaker 01

  Exactly. So, all right, well, we're going to take a short break here, and then we'll be back with more StarTalk Radio. And be sure to check us out at StarTalkRadio.net, and on Facebook, and on Twitter.

• 25:16Speaker 01

  And we're back with more StarTalk Radio Cosmic Queries Edition. I'm Amy Mainzer, your guest host, and I'm here with Chuck Nice.

• 25:22Chuck Nice?

  Yes, yes, and we've got lots of questions and inquiring minds want to know about space probes. So let's jump right back into it.

• 25:32Speaker 01

  Excellent.

• 25:33Chuck Nice?

  This question comes from Twitter. Gabriel Michaels, @DocMichaels, wants to know this. Are ion drives feasible for probes that have planetary or moon/asteroid surface landing missions?

• 25:47Speaker 01

  Yes, well, it turns out that the Dawn mission used just such an ion drive. And I think people are planning to use them for other kinds of encounter and rendezvous missions. So I think it's on the books and people are considering it. Of course, these are systems that kind of allow you to use energy very efficiently, but kind of like an electric car, it takes a long time to build up speed.

• 26:10Chuck Nice?

  Right.

• 26:10Speaker 01

  And a long time to slow down.

• 26:12Chuck Nice?

  So now, can you just, for those who are listening that don't know, because of course I'm very well versed in ion drives, something I, you know, spend my time reading about all day. But how exactly does an ion drive work?

• 26:28Speaker 01

  Right, well, the basic idea is to take something like xenon, and you basically shoot voltage across it. You apply electricity to it.

• 26:36Chuck Nice?

  Right.

• 26:36Speaker 01

  And that produces a reaction.

• 26:38Chuck Nice?

  Poof.

• 26:39Speaker 01

  Right, and it's nice because you get a nice gentle push from it.

• 26:43Chuck Nice?

  Right.

• 26:43Speaker 01

  Instead of using chemicals where you have to put them together and make them explode.

• 26:47Chuck Nice?

  Right.

• 26:47Speaker 01

  Which can also work very well, but can also take a lot of mass.

• 26:52Chuck Nice?

  Right.

• 26:53Speaker 01

  And, you know, they're a little more risky in some sense to use. Although they've got a lot of hardware heritage with the chemical propulsion systems, the ion drives do have some advantages in that they're very, very efficient.

• 27:04Chuck Nice?

  Right.

• 27:05Speaker 01

  And mass is key when it comes to space missions, so people really like that.

• 27:09Chuck Nice?

  So now, if you were to use something like this, you would use a chemical propulsion to get off of Earth?

• 27:16Speaker 01

  Yep.

• 27:16Chuck Nice?

  And then you would engage an ion drive once you're in the vacuum of space?

• 27:20Speaker 01

  Exactly, and then you probably get to say engage ion drive.

• 27:24Chuck Nice?

  Ooh!

• 27:25Speaker 01

  Doesn't that sound great?

• 27:28Chuck Nice?

  I'm sorry, you just got me a little excited.

• 27:34Chuck Nice?

  All right, let's move on. And we got something from Google Plus here, which is Aru Sani is the name. I remember there being a lot of controversy over Cassini's nuclear contents prior to the probe being launched.

• 27:50Speaker 01

  Yes.

• 27:51Chuck Nice?

  Since then, however, I haven't seen or heard much about nuclear probes. Has NASA become reluctant to use nuclear energy for its expletory needs?

• 28:01Speaker 01

  Well, it turns out that the Mars science lander, the Curiosity rover, actually has a small amount of nuclear material that it uses. Now, the thing to keep in mind here is we're not talking about a lot of stuff. It's a pretty small amount, and it's built to withstand a lot of force against it.

• 28:17Chuck Nice?

  Right.

• 28:18Speaker 01

  The thing is, these are not fusion reactions that we're talking about here. It's radioactive decay. So it's a completely different process than fusion.

• 28:26Chuck Nice?

  Right. So this isn't the nuclear reactor that's happening in your submarine that stays underwater for 10 months at a time?

• 28:35Speaker 01

  Exactly. This is basically taking a chunk of plutonium, and you just sort of let it naturally decay and do its thing. And you capture the electrons, the energy that comes off of it. You capture the heat, and you basically turn it into electricity. That's how it works, more or less. So it's a passive process.

• 28:51Chuck Nice?

  Okay.

• 28:51Speaker 01

  You're not really reacting anything together. It's just sort of this lump that sits there.

• 28:55Chuck Nice?

  Sits there. And it's you're just letting it do its own thing.

• 28:57Speaker 01

  Yeah, that's right. And the reason that it has to be used in certain circumstances is because if you get too far from the sun.

• 29:03Chuck Nice?

  Right.

• 29:03Speaker 01

  What are you gonna do?

• 29:04Chuck Nice?

  Right. You don't have the sun's light, or heat, or power, or anything like you can't use solar energy.

• 29:09Speaker 01

  Nope. The sun and Jupiter just kind of looks like a star, a bright one.

• 29:13Chuck Nice?

  Right. But still, that's what it looked like the way Jupiter looks to us in the night sky.

• 29:16Speaker 01

  Exactly. So the problem is, is you got to have something to power your spacecraft.

• 29:20Chuck Nice?

  Gotcha.

• 29:21Speaker 01

  And they use, you know, little chunks of this nuclear material.

• 29:23Chuck Nice?

  That is fascinating. Very cool. All right. Luke Skorron wants to know this, or Skalron wants to know this. After chemical rockets, ion thrusters, and thermal nuclear propulsion systems, what's the next big step in space propulsion? And how much longer do we have to wait for a functional warp drive? By the way, you know, that's his real question. You know that other stuff was just to get to, "When do we get in a warp drive?" So...

• 29:53Speaker 01

  I know. You know, I have to say, as a professional physicist, I am sorely disappointed that we don't have warp drive. I really want one. It'd be really nice to be able to skip traffic, wouldn't it?

• 30:03Chuck Nice?

  Wouldn't it? Yeah.

• 30:06Speaker 01

  That would beat the subway.

• 30:07Chuck Nice?

  So are there any new propulsion systems on the horizon? Do we think there's some kind of breakthrough for space propulsion?

• 30:14Speaker 01

  Well, chemical propulsion is our main means, and the ion drive is the new latest thing. People are working on other technologies, but they're really pretty hard. It's gonna be a while, unfortunately, until we have that warp drive. Until then, we've gotta keep doing research, fundamental physics. Eventually, some smart person will figure it out, I hope.

• 30:31Chuck Nice?

  Oh, there you go, buddy. Wait is the answer.

• 30:34Speaker 01

  Yes. Alright, well, it's time for a short break, and then we'll be right back with more StarTalk Radio Cosmic Queries Edition. Check us out on Twitter at StarTalkRadio.

• 31:02Speaker 01

  Welcome back to StarTalk Radio, and I'm here with my co-host Chuck Nice, and it's time for the lightning round.

• 31:08Chuck Nice?

  Yes, it is, Amy, and this is where you will answer as many questions as quickly as possible, so we can get to them, and when you have finished, we will hear... There you have it. So you ready?

• 31:21Speaker 01

  Yeah, so what do we say?

• 31:22Chuck Nice?

  Lightning round. Engage.

• 31:24Speaker 01

  Yes.

• 31:25Chuck Nice?

  Alright, this is from Luke James, and he wants to know this. "How feasible would it be to send a probe to a solar system with an Earth-like planet? And if one could even make it, would it be possible for one to detect signs of life?"

• 31:39Speaker 01

  Ooh, okay. Well, other solar systems are really, really, really whopping far away. The nearest star to our sun is four light-years away. If we were traveling at the speed of light, which we cannot do, it would still take us four years to get there, and we can't travel anywhere close to the speed of light. If we could someday, maybe, we might be able to find signs of life, but really, I think our best bet is to stay here on the ground and try to develop the technologies that we can use here.

• 32:03Chuck Nice?

  Nice. So the answer is, we're gonna be receiving guests, not going to find them.

• 32:08Speaker 01

  Yes.

• 32:10Chuck Nice?

  Google Plus and Petros wants to know this. How long does it take for a telescope to capture an image? Do you have to point it at a distant object for hours? Or is it pretty much instantaneous? Now, he's talking about once you pass the atmosphere and you're in a probe.

• 32:27Speaker 01

  You got it. Okay, so if you're a telescope in space, let's say we're the Spitzer Space Telescope and we want to look at an exoplanet. Depends on the kind of object. If it's really far away, it takes a lot longer. And it turns out that the farther away, more distant something it is, the fainter it is. So it takes longer for us to gather information, gather light from that object. So basically, it's a question of how faint it is. If it's a really bright object and it's close by, not so very long at all, maybe even just a couple of seconds. If it's a very distant galaxy, hours and hours.

• 32:57Chuck Nice?

  Nice. So it really works just like a camera?

• 33:00Speaker 01

  Exactly, yeah. If you've got low light, you gotta take a long exposure.

• 33:03Chuck Nice?

  Doggone, nice. Okay, Francisco Escobar Prado wants to know this. Well, he's from Costa Rica. I thought he was joking at first. What does NASA do with probes once they have completed their task?

• 33:15Speaker 01

  Ah, very good question.

• 33:17Chuck Nice?

  Okay, now this is what I want to know. Do we get them back, really?

• 33:20Speaker 01

  Sometimes we get them back.

• 33:21Chuck Nice?

  Oh, okay.

• 33:21Speaker 01

  Yeah, there've actually been a couple of sample return missions, which even come back and re-enter into the Earth's atmosphere.

• 33:27Chuck Nice?

  Okay.

• 33:27Speaker 01

  But by and large, most probes are gone, gone, gone. Now, if it's an Earth-orbiting satellite, we actually have requirements to not create space junk. And we deliberately plan to de-orbit our satellites or let them decay in the Earth's atmosphere where they are designed to burn up completely.

• 33:44Chuck Nice?

  Nice. Okay, this is from me. You say space junk. So is there like a junkyard in space? Do we need like a Sanford and Son for our space?

• 33:56Speaker 01

  Yeah, there is a tremendous amount of space junk up there right now. And I think we have a business opportunity here, you and I, Chuck. I think we should start our own space junk company. We could be Sanford and Son in space.

• 34:13Chuck Nice?

  All right. Excellent. Let's move on to Ramon Pinzon from Mexico City. He wants to know this. If we could travel at the speed of light where time doesn't exist, how would our biology be affected while we travel? Now, that really doesn't work for probes because we don't have people on probes.

• 34:35Speaker 01

  That's right. So if a person is actually traveling close to the speed of light, we know from theory that there should be something called time dilation. They would actually age more slowly the faster they go. So this is the ultimate in anti-aging.

• 34:49Chuck Nice?

  Nice.

• 34:49Speaker 01

  Just go really, really, really fast. And in fact, the time dilation that astronauts on the space station experience is a very, very tiny amount though, because they aren't going a very large fraction of the speed of light, even as fast as they go.

• 35:02Chuck Nice?

  Nice. Okay. Joseph Breda wants to know this. Space is so ridiculously insanely mind-boggling big. Is it really feasible for humans to travel between star systems?

• 35:18Speaker 01

  Oh, boy. Well, not with the physics we have today. It would take many, many, many generations, lots of generations, in fact, to even go to the nearest star, which is four light years away. That is incredibly far. It's taken about nine years for the New Horizons spacecraft to go at top speed to Pluto. And that isn't anywhere close to the nearest star. So unfortunately, we need that warp drive we were talking about.

• 35:40Chuck Nice?

  Yes.

• 35:41Speaker 01

  That'll do.

• 35:42Chuck Nice?

  There you go, Joseph. Not gonna happen, buddy. Jace Thorson wants to know this. If it takes three months to get to Mars, is that the time perceived by the astronauts on the shuttle or on Earth?

• 35:57Speaker 01

  Ooh, I think it takes a little bit longer to get to Mars in practice. Yeah, it's a little, little, little more than three months. But, you know, our spacecraft do get there. And it takes, I think it's about nine months or something like that for the spacecraft to get there. And we do have to actually account for the speed of the spacecraft when we make the spacecraft's clock. It's actually because of time dilation. This fact that if you go faster, your perceived time is actually a little bit slower.

• 36:20Chuck Nice?

  So they do make an adjustment for that?

• 36:21Speaker 01

  So we do make an adjustment for the speed of the spacecraft.

• 36:24Chuck Nice?

  Look at that, Jace. Great question.

• 36:26Speaker 01

  There you go.

• 36:27Chuck Nice?

  Nice. All right, Morgan Noonan wants to know this. Why can't we set up a chain of probes that repeats data streams to accelerate signals? Kind of like cell towers.

• 36:39Speaker 01

  Well, funny thing, we actually have that at Mars. There are orbiter spacecraft that relay data from the rovers back to Earth.

• 36:47Chuck Nice?

  Sweet!

• 36:49Speaker 01

  Yeah, so we actually have Wi-Fi in space. And that's about all the time we have on this show. Well, this has been great Chuck, and thanks a lot. I'm your guest host tonight, Amy Mainzer from the Jet Propulsion Laboratory, filling in for Neil deGrasse Tyson. And please be sure to check out Chuck at ChuckNiceComic on Twitter.

• 37:08Chuck Nice?

  Thank you!

• 37:09Speaker 01

  And check out StarTalkRadio.net. And until next time, clear skies, everyone.